Seven things we want from Resident Evil 7 DLC | GodisaGeek

Gary Bailey: "Whatever we get from the free Not A Hero and the as-yet-untitled paid DLC, it will be great just to get more story content for one of this year’s best games. It will certainly be nice to see whether that really is Chris Redfield, or if the crazy fan theories have any weight to them."

Its pretty obvious why Chris is working for Umbrella. Umbrella was disbanded affer RE 3. It seems obvious to me thay Umbrella has been rebuilt and repurposed to be an organization for good. Using their research on BOW's would be a huge help. Also, notice the logo is now blue instead of the more ominous red.

As for Chris not being a muscle-bound brute anymore, I'm pretty sure its just a different artistic take on the character. This game had a more realistic take on the art style than the previous games. I think thats all it is.